I/U stage D1 clone with 2sk389 finetuned...

[DoctorWho70]

and this is the d1 stage by klaus...
it's only a half.. the img became too big... the other part it's mirrored...

[Nelson Pass]

Nice work, guys.

[UltimateX86]

Originally posted by DoctorWho70
and this is the d1 stage by klaus...
it's only a half.. the img became too big... the other part it's mirrored...

it sounds well?

no buffer?

[DoctorWho70]

the out stage was posted on page 3 ...
I don't know how it sounds because i am modifying the original project made by klaus for using the d1 stage by mr. Pass on a tda1547 in the switched cap pins bypassing the embedded opamp... i am simulating the circuit to made the printed circuit an mount it to test the sound, after this i could maybe improve the sound modifying the bias currents or caps or i don't know..
Klaus and others tells that this stage sounds very well (excellent sound..)... but my problem is that i have to use for a differential stage with 2 tda1547 (one for channel).
So i have to sum the signal with a discrete op amp stage and a buffer...
I want to replace the entire power supply/out stage board of my cd10 with a new +/-15 v +/-30v (for this stage) totally renewed with a 4 jung discrete/op amp regulators... and i want to place all this circuit on a 15x15cm board...
I've made some modifies on the differential stage... i read on an old data sheet of national that using two double fet configured as in the schematic in the image could improve the CMRR...
Anyone have tested this configuration? better or worse than a single fet?

[DoctorWho70]

some improving (or this is what i think) on the stabilization of the voltage on the fet gates of the klaus stage...
Please post suggestions about this schematics... also laughs are accepted...
Bye and thanks for this fantastic board...
DoctorWho

[steenoe]

Bye and thanks for this fantastic board...

I would love to have a D1, PCB! Who say's Group-buy??

Steen.

[UltimateX86]

THX 4 your answer

for the CCS, we can remove the ZTX? like the png

we can keep a differential pair in the IV?

In fact I would like to do a line preamp like Aleph P1.7 but with 2SK389/109, capacitor coupled FREE ! (thus with servo) and with an output buffer.

AND one IV on the same structure

[DoctorWho70]

for the CCS, we can remove the ZTX? like the png

This is what i read...

Originally posted by Klaus

...
I tested the simple CCS with just one 2SK170. Due to strong variations of the unmatched FETs I had to set the R to the right value to get the required current. Also somehow the sound was worse, not so powerfull. Maybe the CCS combination of the bipolar transistor with its high gain and the bigger IRF610 gives the "stronger" CCS, working more ideal? I don´t know, but I do not care about some transis more or less...

I like the P1.7 CCS because the basis-emitter refernce voltage of the bipolare transi is a very good reference, no matching required.

Regards

Klaus

This is what Klaus tells about the configuration of simple ccs with fet+resistor or the other with the ztx... i followed the tests of klaus... but if you want you can modify the mounting of the pcb and bridging with a wire or with the gate resistors the components that you want to cancel... this is not a problem... you could test all the configurations without problems with a complete pcb... more difficult is adding components on a simple pcb instead to remove some parts... this is what i think when i project a board, when there isn't problem of space...

we can keep a differential pair in the IV?

maybe it's possible but i have to mantain the zeros points for the common of the dac outs, for me it is not good to place a single ccs in the differential stage for having the d1like stage and the differential op amp in the same chain... the modifiying of the currents move the voltages of the sources of the two main fet in the d1 stage... so for a my idea (that can be wrong) this can't be a good stage... (sorry but my explication in english can be very hard to know... )
So i thinked to use a separate stage to sum the two signals...
But this can be wrong....

capacitor coupled FREE !

I'd love to have a complete stage without capacitors coupling... but i have to fight ever with some many volts of dc voltage to decouple in the final stage , i thinked about to resolve this problem but for the moment i haven't a solution...
But maybe there is a simple solution that i've not thinked... or that i don't know....

ideas and suggestions are welcome...
for the pcb i think to project it with orcad... and after i would like to do a homemade pcb printing the design on a transparent paper and doing a obscenity to mount and test ( and maybe to leave it in the definitive mounting...).
I've asked to my boss how much costs doing a pcb double face with a ready design (not made by third parts) and in italy it can costs for few pieces some hundreds euros... (i live in italy and i think that there there is the most great thieves in fact of components selling and tecnologic services, here the free market doesn't exisists...).
i maybe can design the complete pcb, and i can subsequently post it here... if someone know a cheaper way... my work is free, but please help me in projecting this stage
Bye to all
DoctorWho70

[Klaus]

Originally posted by UltimateX86



it sounds well?

no buffer?

Hi,

YES, it does! It is funny, the first time since years I just want to listen to music and no more want to test alternative settings. It just sounds like "real music". The bass and voices especially are just incredible.

Maybe the transparency is just 95% of e.g. a super clean OPA627, but the musical flow and feeling of the music is just "right" – missing feedback maybe.

I prefer the buffer - if the output load plus cable and so on become part of the active I/U load resistor I can not imagine that this is so fine - one buffer stage IMHO is not so bad.

Regards

Klaus

[samoloko]

very Interesting tuning
Is this mod really better sounding compared to stock d1 I/V
also I like to know what Is the reason to try 2sk389 instead of IRF610 for I/V converter
are the schematic use single 2sk170 from 2sk389 or two In parallel